The present invention relates to open end rotor spun yarn and the method of producing such yarn. More particularly, the present invention relates to such a yarn and method wherein the presence of wrapper fibers is accentuated to provide a mottled appearance in the yarn and resulting fabric made therefrom.
As the technology of open end rotor spinning of yarn has developed, the primary goal has been to produce a yarn having the characteristics and qualities of ring spun yarn, i.e., a relatively strong, soft, uniform yarn. The main obstacle in obtaining this goal has been the undesirable inherent formation of wrapper fibers on the surface of the yarn, which result from some fibers not being twisted uniformly with the other fibers but rather wrapped tightly around the yarn and having ends that project from the wrapping without significant intertwining in the yarn, thus creating a harshness in hand, an undesirable appearance, and a relatively weak structure.
In the process of open end rotor spinning, the loose fibers are fed to the conical inner wall of the rotor with the fibers transferring along the wall into the rotor groove from which they are withdrawn and twisted in a generally orderly manner to form the yarn. The fibers acting in this way form a main strand that can be made by controlling the processing parameters to have characteristics and qualities closely resembling those of ring spun yarn. However, due to the nature of open end rotor spinning all of the fibers do not follow this orderly formation. Rather, some fibers, particularly those that feed to the rotor groove as the revolving drawoff of the yarn formation passes the yarn feed location, do not intertwine orderly with the other fibers but wrap rather tightly around the yarn and have ends that project randomly. These wrapper fibers not only serve no purpose and provide no strength to the yarn, but they make the yarn coarse in hand and sight. Furthermore, we need to increase the twist imparted to open end spun yarn in order to enhance the strength necessary to be able to spin fine yarn has accentuated the wrapper fiber formation.